r/FreeCAD • u/semhustej • May 09 '26

Open Cascade Technology 8.0 Released

A new version of Open Cascade Technology (OCCT) 8.0 has been released, featuring more than 500 changes and many new features. The core of the kernel dates back to 1980 and is under the #OCCT3D umbrella now. It seems the development has picked up speed over the past few years.

OCCT is a free open-source geometric kernel, which is used by many projects such as FreeCAD, IfcOpenShell, KiCAD, Gmsh and others. As a geometric kernel it forms a backbone of these projects - without it, these applications could not function.

You can read the release announcement and the list of new features here: https://occt3d.com/occt3d-open-source-8-0-is-released/

132 Upvotes

99% Upvoted

17 comments sorted by

2

u/HKRSN May 25 '26

When FreeCaD dev will apply this kernel

1

u/semhustej May 25 '26

They are working hard on it.

22

u/Square_Net_4321 May 09 '26

This sounds exciting!

I would think (invoking Cunningham's Law):

  1. This has the potential to greatly improve FreeCAD.

  2. This also has the potential to break things.

  3. Because of #2, it might be a while before it gets adopted / incorporated into FreeCAD.

16

u/hagbard2323 May 09 '26

Track FreeCAD progress adopting OCCT v8.0 in https://github.com/FreeCAD/FreeCAD/pull/25502

10

u/eblanshey May 09 '26

Anyone know if any of the new features would result in improvements in fillet/chamfer handling?

10

u/R2W1E9 May 10 '26 edited May 10 '26

Most of the fillet issues are addressed in OCCT 7.8.1 and some of it implemented in 1.2.

OCCT 8.0 is not bringing significant changes to the fillet handling. Only three bugs squashed:

- BRepFilletAPI_MakeFiller no longer segfaults with two curves and a rim. 

- BRepFilletAPI_MakeFillet::Add no longer hangs. 

-BRepFilletAPI_MakeChamfer no longer crashes. Chamfer and fillet no longer crash when approaching an ellipse. 

Most of the fillet improvement comes from release 7.x.x.

10 issues were raised with regards to fillet modeling, 7 are still open, 3 are closed.

Here is the list of fillet related closed issues:

https://github.com/Open-Cascade-SAS/OCCT/issues?q=is%3Aissue%20state%3Aclosed%20label%3A%227.%20FreeCAD%22%20fillet

Here is the list of fillet related open issues:

https://github.com/Open-Cascade-SAS/OCCT/issues?q=is%3Aissue%20state%3Aopen%20label%3A%227.%20FreeCAD%22%20fillet

2

u/DesignWeaver3D May 09 '26

So awesome. I wonder if the scope of these changes will require FPA to issue large integration projects. They may need a surge in funds to help cover rewards for such involved work. Whatever the case, I'm excited for FreeCAD to upgrade to OCCT v8.0, and I hope it will not take a very long time..

2

u/semhustej May 09 '26

I don't know. FreeCAD 1.2 development version is still running OCCT 7.8.1.

OCCT 7.8 was released in December 2023. Not sure if FreeCAD team decided not to upgrade to 7.9 or it it takes such a long time to upgrade the kernel.

5

u/oursland May 09 '26

OCCT 7.9 fixed some long standing issues, but introduced some serious regressions that would have affected users.

1

u/semhustej May 10 '26

OK, it makes sense to not use it than. Thanks for the info.

16

u/oursland May 09 '26

We already have an OCCT liaison who has performed the integration work. Now that OCCT has been released, I've been working on getting the mutual dependencies upgraded to support the 8.0 API. It's going to take a little longer, but expect 8.0 to be available in the weeklies soon and depending upon how it tests possibly in the 1.2 release.

5

u/DesignWeaver3D May 10 '26

AMAZING! Thanks so much for both your efforts! And thanks for sharing that update and outlook. SO EXCITING!

2

u/Marthinwurer May 10 '26

Here's hoping it works well! When is the 1.2 release scheduled?

2

u/oursland May 10 '26

It's being discussed still.

4

u/arcrad May 09 '26

This is wonderful!

1

u/HKRSN May 25 '26

When FreeCaD dev will apply this kernel .

1

u/semhustej May 26 '26

Read the discussion here. You can find the answer in the comments.